不同类型土壤对Fe0还原地下水硝酸盐的影响

采用批试验方法研究中国具有代表性的7种土壤（陕西杨凌 土 娄 土表层、陕西杨凌 土 娄 土粘化层、重庆忠县黄壤表层、湖北十堰黄棕壤表层、陕西汉中黄棕壤表层、陕西汉中水稻土及辽宁抚顺棕壤表层）存在下，对Fe⁰还原脱除地下水中硝酸盐的影响并考察土壤性质对硝酸盐去除的影响。试验表明，不同类型土壤对Fe⁰还原硝酸盐的影响不同，以汉中水稻土和抚顺棕壤的促进作用最为明显；除汉中水稻土外，其他土壤灭菌处理对Fe⁰还原硝酸盐影响不大；不同初始pH对土壤存在下Fe⁰还原地下水中硝酸盐有不同的促进作用，初始pH为3.0和4.0条件下，不同土壤的促进作用差异不明显，此时pH为反应的主要控制因素，反应进行5 h就基本结束，随着初始pH的不断升高，在pH为5.0和6.0的条件下，不同土壤间促进作用的差异性渐渐显现出来。陕西汉中水稻土和辽宁抚顺棕壤对Fe⁰还原硝酸盐有促进作用；土壤中的反硝化微生物对Fe⁰还原硝酸盐有一定的促进作用，同时土壤有机质含量也对硝酸盐的还原有促进作用；不同初始pH对于土壤 Fe⁰体系具有影响，初始pH越小，还原效率越高。

Influence of Nitrate Removal from Groundwater by Fe0 with Different Types of Soil

Different types of soil have certain influence on in situ nitrate removal from groundwater by Fe⁰. In this article, the batch experiment of nitrate reduction by Fe⁰ was conducted with seven typical soils, including surface Lou soil in Yangling Shaanxi, argillic horizon Lou soil in Yangling Shaanxi, surface yellow soil in Zhongxian Chongqing, surface yellow brown soil in Shiyan Hubei,surface yellow brown soil in Hanzhong Shaanxi, paddy soil in Hanzhong Shaanxi and brown soil in Fushun Liaoning. The results showed that the paddy soil from Hanzhong Shaanxi and brown soil from Fushun Liaoning have the best performance. The sterilization had less effect on the nitrate reduction rate of other soils.Whereas the other treatments had no obvious influence on nitrate removal. It had different promoting actions between different initial pH. Under 3.0 and 4.0 initial pH circumstance, there were no obvious distinctions on nitrate removal between different soils treatment.And then, the initial pH had been the main factor in the reactions, which only lasted in 5 h. With the increase of initial pH(5.0 and 6.0), the distinctions had emerged gradually in different types of soil treatment. The results indicated that paddy soil in Hanzhong Shaanxi and brown soil in Fushun Liaoning have positively promoting actions on nitrate removal. The denitrifying microbes in the soil promoted the reaction of nitrate reduction by Fe⁰, at the same time, soil organic matter, soil mechanical composition, pH and other properties also related to the efficiency of nitrate removal. The initial pH had influence on soil Fe⁰ system, the lower initial pH, and the higher the reductive efficiency.